Method of separating nuts from kernels in a nut-and-kernel mixture

Abstract

Disclosed is a method of separating nuts from kernels in a nut-and-kernel mixture in terms of the sound characteristic of nuts or kernels. Specifically each and every nut or kernel is allowed to produce sound to distinguish nuts from kernels in terms of nut-representative, 6-to-16 kilohertz high sound components detected, if any in the produced sound.

We claim: 
     
       1. Method of separating nuts from kernels in a nut-and-kernel mixture comprising the steps of: feeding nuts and kernels one by one;   rolling and/or dropping nuts and kernels to produce sound;   collecting and analyzing the so produced sound to distinguish nuts from kernels in terms of the sound characteristic of nuts or kernels; and   separating nuts from kernels in terms of the characteristic sound representing nuts.   
     
     
       2. Method of separating nuts from kernels in a nut-and-kernel mixture according to claim 1, wherein nuts are distinguished from kernels in terms of the sound component whose frequency range covers about 6 to 16 kilohertz. 
     
     
       3. Method of separating nuts from kernels in a nut-and-kernel mixture according to claim 2, wherein the step of rolling and/or dropping nuts and kernels includes the step of using a sound-deadening type mono-screw conveyor for rolling nuts and kernels individually and/or using a sound-deadening resin plate on which nuts and kernels fall one after another. 
     
     
       4. Method of separating nuts from kernels in a nut-and-kernel mixture according to claim 1, wherein the step of collecting and analyzing the so produced sound includes the step of: collecting and converting the sound to alternating current voltage; amplifying the alternating current voltage; filtering and separating the characteristic component of alternating current voltage whose frequency range covers about 6 to 16 kilohertz, if any; and permitting a separator to be controlled in response to the characteristic component of alternating current voltage. 
     
     
       5. Method of separating nuts from kernels in a nut-and-kernel mixture according to claim 4, wherein the separator comprises a microphone for collecting the sound produced by the rolling and/or falling nuts and kernels, an amplifier connected to the microphone, a filter circuit for selectively passing the characteristic component of alternating current voltage, a relay circuit connected to the filter circuit, a solenoid-operated valve connected to the relay circuit for operating in response to appearance of the characteristic component voltage signal, a pneumatic piston cylinder operatively connected to the solenoid-operated valve, and a collecting chute equipped with gate means controlled by the pneumatic piston cylinder for opening or closing.